Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Network latency in a packet-switched network may be measured one-way (the time from the source sending a packet to the destination receiving the packet) or round-trip (the one-way latency from source to destination plus the one-way latency from the destination back to the source). While round-trip latency is more often used, because it can be measured from a single point, it may obscure/hide the amount of time that a destination system spends processing the packet. Some software platforms employ pinging that can be used to measure round-trip latency. Pinging performs long packet processing; it merely sends a response back when it receives a packet.
However, a typical packet may be forwarded over many links via many gateways, each of which may not begin to forward the packet until it has been completely received. In such networks, the minimal latency may be defined as the sum of the minimum latency of each link added to the transmission delay of each link. This latency may be further increased by queuing and processing delays. Queuing delays may occur when a gateway receives multiple packets from different sources heading towards the same destination. Since typically only one packet can be transmitted at a time, some of the packets may be queued for transmission, incurring additional delay. Processing delays are incurred while a gateway determines what to do with a newly received packet. The combination of propagation, serialization, queuing, and processing delays may often produce a complex and variable network latency profile.
The measurement of packet processing time—a component of total network latency—in a host may involve a complex setup. The complexity may increase if the host is remotely placed from the administrator (e.g., as in a cloud).